Hey AG, Tim here, uh, u mean 5/64 rings......5/32 ring wud be HUGE, mild oversight, on a vid......the proposed solution is SPOT ON!!!...rods are tweaked, crank needs to be turned, if its actually cheaper to get another crank, DO IT!!...for me, (Pontiac guy)....i'd have to turn the crank, as a new one is SUPER expensive.....but ur analysis/recomendation for solution, i feel is spot on!!.....once again, an enjoyable, Sun morn, sippin coffee vid.....TY sir!!.....PEACE to you, lets hope ur customer is ok with whats gotta happen!!
Yes sir, back in the early seventies when there was a machine shop on every corner and the manufacturers had not absorbed all of the costs of machining engines taking an engine to a machine shop was cost effective. Nowadays with all of the manufactured items being just cheaper to buy and install, and the fact that machine shops are not on every corner it makes sense to go the route you have explained. I remember a radiator shop that I used to do business with was able to sell me a new radiator for just ten dollars over the cost of recoring an existing unit. And for ten dollars more you got a new unit with new transmission cooler if you used an automatic and was using the stock set-up. Also it was better for the dealer as all he had to do was pull a new one off the shelf. Unless it is an exotic piece of equipment where it is cheaper to repair or remanufacture, or one needs to keep things original (for restoration purpose) it is best to go the route you described.
Excellent video. Thanks for the update. Nothing is ever easy when it comes to old engines (or old cars for that matter). While it may cost a little more, Paul will be able to rest easy knowing that when the work is finished he will have a solid, reliable engine that will serve him well for a long time. Thanks again for the update. I'm looking forward to your follow-up videos.
I'm of the mindset that even though a new part may be comparable in price to machining an old part, I'd rather re-use where possible. I know the old part is a quality part due to surviving, it diminishes the throw-away attitude, it does not support the habit of chasing the cheapest global labor manufacturing of the last 20-30 years, and most important to me, it supports local skilled labor and knowledge. Once machine shops are gone, we won't have any option other than to be forced to accept whatever quality control the part on the shelf has.
Those rods are 55 years old and their life is a mystery. New rods are a loss for the machine shop, but don't worry, we have LOTS to do without having to resize old rods.
I have done the same lately with a 350 chevy scat rods bolts floating save $$ hang pistons my self crank std did bore .030. I bought 292 heads over the counter in the 80s wish I still, had them, angel milled 0.125 mild porting trw small pop up pistons, stock rods Z28 optional cam, holley manifold, 750 holley, it made 548 hp that was good power in the day. in a front engine dragster ran 8.40 152mph. thanks alen your getting better with the videos keep them coming. well we get to hear this engine run?
That reminded me, a good head. When you have conned somebody into sponsoring you, you have to be at the track. One Friday in the early 1990's in dire need of an engine for the weekend, grabbing things we had sitting there, took a 1976 smog motor Chev 350 Malibu short block, dished pistons, normal factory stuff, we didn't even pull the pan on it, stuck in a GM 2nd design off road cam in it, bolted on a set of ported 292 heads, a Holley Strip Dominator and an 850 Holley race carb. I swore to keep it under 6000 rpm because of the cast crank. On the first pass it ran 12.06 and we agreed to spin it to 6500 and see if it would make the 11.99 (Must qualify) cut off for the Pro Bracket, it ran 11.92 and proceeded to last for three rounds of eliminations then it went home and became parts on the shelf again. I have no idea what power it made that weekend, but it was moving a 3000lb steel Nova with TH400 and a 4.89 gear. It should have been a hell of a shake-up for my thinking, a weird magic parts combo that ran on pump gas. It did its job and I didn't listen, I'm listening now and it is too late. )-:
@@doomman700 It surprised the heck out of me too. The cam was intended by GM for Trans Am racing way back in the sixties and we thought we'd end up running in the 12's at best with the combo.
Seeing rings aligned with bad leak down numbers like those few cylinder have makes me believe those cylinders may have been overheated causing the rings to anneal and lose their tension against the cylinder wall. I’d go out on a limb and say that the engine was detonated causing the rod and main bearing damage being shown. I once made a mistake helping a friend out with an engine in similar conditions. I failed to inspect the ring lands of the pistons when installing the new rings. We could not get that engine to quit rattling. It seemed to want to detonate no matter what we tried. The long and short. The ring lands were worn out causing the rings to have excessive clearance in the lands. It wasn’t like this pistons were high mileage it had been rebuilt with very few miles. Pistons looked very nice once we cleaned them. It was a learning experience that I never forgot. At that moment in time that choice saved about $100.00 for that set of pistons. $100.00 would not have blown that budget. It’s just not worth it when you’re building an engine with cast or hypereutectic pistons.
Good points Hugh. I have not done a thorough cleaning and inspection of the pistons. They are TRW7064P. I will look for the damage you described and new pistons are an option if necessary. A little more than $100. now but worth the cost if it is required. Thanks for sharing your experience and advice.AG
Thanks Hugh, since your comment I removed the rings from #4 piston. The ring lands look ok and the fit of the ring is normal. The bore is 4.002" and the clearance is .0035" +/-. i haven't had a chance to check #4 intake valve yet, it could be the cause of leak down also. The clearance is in the middle of Forged and cast pistons and acceptable for both. The pistons look to be forged to me, but i can't find info to decode them. They are TRW7064P. If that P was an F I would conclude that they were forged. Does anyone know? AG
It’s been a long time since I’ve dealt with TRW numbers. I’m thinking maybe the P designation is press fit and the f maybe floating but that is not solid memory. I tried looking that number up earlier today when you initially responded and couldn’t get any information either. Take the top ring at the ring gap and twist the ring. Pull one end gap towards and one away. If they don’t spring back in line with one another that could be a sign of overheated rings.
I'd recommend going with a set of gap less piston rings which are excellent for sealing up the combustion chamber and providing increased cylinder pressure !
Maybe 5/64 rings, not 5/32? Once you've gone that far with new pistons, wouldn't it make sense to have the block honed with a torque plate, perhaps .005" over and have pistons made to fit so the ring seal would be perfect? Racetec does a great job of making whatever I ask for, it saves the cost of boring the block. I have a 572 tall deck in that I am doing that with right now.
Barry, On the ring seal, a MS Sunnen Hone is better for sure, but I have had pretty good leak down results this way. I am trying to do what is best for the customer.AG
@@goldsgarage8236 Yeah, not trying to be too picky, but once you replace crank and rods, might as well put a good piston in it with 1/16 rings and have an all new shortblock. Keep up the good videos!
Have a close look at the ring grooves, if they are worn the new rings won't seal and you'll end up with excessive blowby and potentially oil consumption. Pressing the pistons off is a bit of a gamble because they can distort or even crack during the process. The other weak point is the clip groove, it can be distorted during the removal process. Another consideration is Federal Mogul changed from double tru-arcs to a single round wire lock a number of years back, and the grooves in the pistons are different. I realize budget is important, but you can buy a budget Eagle balanced rotating kit that's quite inexpensive, it might make more sense in this case because you don't have the labor to remove pistons off rods, have them pin fit, clean up the ring grooves, etc. The new rods are about 50 grams lighter than factory rods, and a new replacement crank is balanced to a mystery bobweight, so you could end up with the dreaded vibration in the mid 2000 RPM range.
Yarrda, you are my mentor, thanks for the info. You have me thinking, or rethinking my plan. These are forged pistons, the bore is on the high side, so i would have to go with forged again if i do replace them. Here is a question, how do you think a 1972 block is standard bore and still in spec, even after at least one rebuild. Thanks as always for good advice.AG
Wow, I didn't expect that much bearing damage! Oil starvation? I remember the rave back then about sbc angled plugs but does it make that much difference? Those pistons look exactly like the TRW's from my '84 vette and it's disappointing that they are press fit. People can get an enitre scat balanced rotating assembly for reasonable prices nowdays thankfully. I would never buy an eagle crank again as I had one break at #7 and found a large void in the casting. Thanks for the follow up!
Thanks DIY, brake clean with air pressure in the cylinder will tell the tale. 5 of 8 cylinders had excellent leak down numbers. I will do a leakdown test again before permanently installing the heads. AG
Interesting debate. For a little more money you can buy new parts OR you can get a machine shop to custom fit your parts. The bearing wear is a real concern. Wouldn't be surprise if there is a crack in the crankshaft in this case and that leans the decision BUT. I want to know why my engine is leaking down 40% eating bearings and knocking. There is a price to this that could very well be worth the investment. .... And then again if I know these engines eat these cranks then I move on. To much missing information to make an informed decision for me here.
My memory is that the 292 'turbo' angle plug heads did not come on any vehicle from the factory. They were only available over the counter from GM around 1975 on
you are correct, the 292 angle pug heads were over the counter only. the 1970 Z/28 and Corvette LT1 heads were 186 casting. the 292 heads were out just prior to the early "Bowtie" heads. the 292 was the first over the counter heads for the SBC for Chevy performance. there were other performance heads the were pushed out the back door to race teams. Like the 461X and 339x heads. the X at the end of the casting indicated that they had bigger intake runners. there was also a strait plug version of the 292 head. casting 492. they were the best flowing heads until the bowties came out, but the Vortec head is still better than any of the camel humps like the 186, 461, 462 or the 292 and 492. the newer Bowtie stuff and pretty much any aftermarket aluminum head is still better. I have quit using cast iron heads for anything but marine application. but for a cheap budge build for a marine small block, I go Vortec every time. summit racing makes a clone of the Vortec but a better casting to prevent the cracks Vortec's are known for. it's my new favorite for any marine small block. and it will take a .490 lift cam out of the box. but can be machined to take a higher lift cam.
@GoldsGarage8236 from what you have described about the bearings and knowing that the engine was around 10:1 compression, and if it was run on pump gas, makes it sound like detonation to me. when detonation happens in an engine the piston is still pushing up in the cylinder and the detonation will cause the piston to transfer the force of the detonation down the connecting rod and into the upper rod bearing, it will also cause the bearing to get "pounded out", losing bearing crush, and loose in the connecting rod bore, exactly like you showed in the example. and it will make the journals on the crank egg shaped. you will also see wear on the bottom of the main bearings as you showed, since the crank is trying to be force out the bottom of the block by the force of the detonation. I would also suspect to see wear on the pin bores on the pistons and maybe the ring lands. Detonation will also cause a lot of heat in the engine, this can damage the ring lands on the pistons and if the engine overheated the rings will lose tension, but I don't think it would cause 40% on one cylinder, so i would suspect the exhaust valve on that cylinder. the exhaust valves run hot on the center two cylinders on angle plug heads to being with, which is why the NASCAR engine builders added coolant hose between them on NASCAR cup engines back in the day. i am betting the exhaust valve on the low cylinders need some work. also, detonation will also cause a blown head gasket. which could also cause the low pressure on the leak down test. it would not be blowing out the intake or exhaust ports. and would sound like it was coming out from inside the engine itself. but would be actually coming out the water passages. I would also look at the head gaskets around those low cylinders.
Thanks Shadvan, a very well thought out analysis, coming from a voice of experience. There is a lot here to consider and comment on, and a few things have changed since this video. i will reply to it in the next video update. thanks for contributing to my channel.AG
I asked total seal lake speed Jr he said leading reason for ring gaps to line up is detonation. I had a Windsor we detonated because poor timing mark on scat balancer and it had both early and new marks on one balancer. always pays to cut a grove on the balancer to tdc is what I learnt from that and set the timing pointer. but basically 4 out of 8 pistons rings lined up engine probably had 2hrs on it and trying to find ignition issue for all of it. race boat motor can't quickly change stuff like a car
Allan, hows the oiling system look? That's a lot of copper showing on those bearings and all of them, extreme something or other. I'm assuming this engine didn't have a NO2 bottle in the mix.
Good question Vom. It actually has a high volume oil pump and everything else like the cam and lifters are good. The bearings look pretty hammered for sure, but no evidence of overheating. Also no evidence of detonation on the pistons.AG
Hey AG,
Tim here, uh, u mean 5/64 rings......5/32 ring wud be HUGE, mild oversight, on a vid......the proposed solution is SPOT ON!!!...rods are tweaked, crank needs to be turned, if its actually cheaper to get another crank, DO IT!!...for me, (Pontiac guy)....i'd have to turn the crank, as a new one is SUPER expensive.....but ur analysis/recomendation for solution, i feel is spot on!!.....once again, an enjoyable, Sun morn, sippin coffee vid.....TY sir!!.....PEACE to you, lets hope ur customer is ok with whats gotta happen!!
Thanks Tim, good catch on the rings, thanks for commenting and peace to you also.AG
Yes sir, back in the early seventies when there was a machine shop on every corner and the manufacturers had not absorbed all of the costs of machining engines taking an engine to a machine shop was cost effective. Nowadays with all of the manufactured items being just cheaper to buy and install, and the fact that machine shops are not on every corner it makes sense to go the route you have explained. I remember a radiator shop that I used to do business with was able to sell me a new radiator for just ten dollars over the cost of recoring an existing unit. And for ten dollars more you got a new unit with new transmission cooler if you used an automatic and was using the stock set-up. Also it was better for the dealer as all he had to do was pull a new one off the shelf. Unless it is an exotic piece of equipment where it is cheaper to repair or remanufacture, or one needs to keep things original (for restoration purpose) it is best to go the route you described.
Thanks Billy, a very accurate analysis of what is happening. Thanks for commenting.AG
Excellent video. Thanks for the update. Nothing is ever easy when it comes to old engines (or old cars for that matter). While it may cost a little more, Paul will be able to rest easy knowing that when the work is finished he will have a solid, reliable engine that will serve him well for a long time. Thanks again for the update. I'm looking forward to your follow-up videos.
Thanks for your comments Todd. I am trying to strike a reasonable balance of cost and reliability. Paul will be OK.AG
Glad it was caught before a bearing spun and left a lot of metal debris behind. Stinks having to clean all that up. Thanks for the video!
Thanks Gregg, for sure it would have spun eventually. AG
I'm of the mindset that even though a new part may be comparable in price to machining an old part, I'd rather re-use where possible. I know the old part is a quality part due to surviving, it diminishes the throw-away attitude, it does not support the habit of chasing the cheapest global labor manufacturing of the last 20-30 years, and most important to me, it supports local skilled labor and knowledge.
Once machine shops are gone, we won't have any option other than to be forced to accept whatever quality control the part on the shelf has.
You make some very good points Dad. Its a tough business and margins are thin on both sides. I have to do what is best for the customer. AG
Those rods are 55 years old and their life is a mystery. New rods are a loss for the machine shop, but don't worry, we have LOTS to do without having to resize old rods.
Appreciate the short update videos like this to keep us in the loop. Thanks. Will be watching to see what the decision is moving forward.
Thanks for your comment Kloeppky. AG
Me too mate top comment
I have done the same lately with a 350 chevy scat rods bolts floating save $$ hang pistons my self crank std did bore .030. I bought 292 heads over the counter in the 80s wish I still, had them, angel milled 0.125 mild porting trw small pop up pistons, stock rods Z28 optional cam, holley manifold, 750 holley, it made 548 hp that was good power in the day. in a front engine dragster ran 8.40 152mph. thanks alen your getting better with the videos keep them coming. well we get to hear this engine run?
Thanks Gordon, 548HP is still a good number from a 350. It must have been a fun ride, thanks for sharing.AG
For sure, we will make videos along the way and starting on my test stand. AG
That reminded me, a good head.
When you have conned somebody into sponsoring you, you have to be at the track.
One Friday in the early 1990's in dire need of an engine for the weekend, grabbing things we had sitting there, took a 1976 smog motor Chev 350 Malibu short block, dished pistons, normal factory stuff, we didn't even pull the pan on it, stuck in a GM 2nd design off road cam in it, bolted on a set of ported 292 heads, a Holley Strip Dominator and an 850 Holley race carb.
I swore to keep it under 6000 rpm because of the cast crank. On the first pass it ran 12.06 and we agreed to spin it to 6500 and see if it would make the 11.99 (Must qualify) cut off for the Pro Bracket, it ran 11.92 and proceeded to last for three rounds of eliminations then it went home and became parts on the shelf again. I have no idea what power it made that weekend, but it was moving a 3000lb steel Nova with TH400 and a 4.89 gear. It should have been a hell of a shake-up for my thinking, a weird magic parts combo that ran on pump gas. It did its job and I didn't listen, I'm listening now and it is too late. )-:
That’s pretty good et for off road cam.
@@doomman700 It surprised the heck out of me too. The cam was intended by GM for Trans Am racing way back in the sixties and we thought we'd end up running in the 12's at best with the combo.
Seeing rings aligned with bad leak down numbers like those few cylinder have makes me believe those cylinders may have been overheated causing the rings to anneal and lose their tension against the cylinder wall.
I’d go out on a limb and say that the engine was detonated causing the rod and main bearing damage being shown.
I once made a mistake helping a friend out with an engine in similar conditions.
I failed to inspect the ring lands of the pistons when installing the new rings.
We could not get that engine to quit rattling. It seemed to want to detonate no matter what we tried.
The long and short. The ring lands were worn out causing the rings to have excessive clearance in the lands.
It wasn’t like this pistons were high mileage it had been rebuilt with very few miles. Pistons looked very nice once we cleaned them.
It was a learning experience that I never forgot. At that moment in time that choice saved about $100.00 for that set of pistons. $100.00 would not have blown that budget.
It’s just not worth it when you’re building an engine with cast or hypereutectic pistons.
Good points Hugh. I have not done a thorough cleaning and inspection of the pistons. They are TRW7064P. I will look for the damage you described and new pistons are an option if necessary. A little more than $100. now but worth the cost if it is required. Thanks for sharing your experience and advice.AG
Thanks Hugh, since your comment I removed the rings from #4 piston. The ring lands look ok and the fit of the ring is normal. The bore is 4.002" and the clearance is .0035" +/-. i haven't had a chance to check #4 intake valve yet, it could be the cause of leak down also. The clearance is in the middle of Forged and cast pistons and acceptable for both. The pistons look to be forged to me, but i can't find info to decode them. They are TRW7064P. If that P was an F I would conclude that they were forged. Does anyone know? AG
It’s been a long time since I’ve dealt with TRW numbers. I’m thinking maybe the P designation is press fit and the f maybe floating but that is not solid memory.
I tried looking that number up earlier today when you initially responded and couldn’t get any information either.
Take the top ring at the ring gap and twist the ring. Pull one end gap towards and one away. If they don’t spring back in line with one another that could be a sign of overheated rings.
Im sure you will have a good mill when you are done 👍
Thanks for the update 🍵
Thanks Jumbo, but it is turning out to be a convoluted path getting there. AG
I'd recommend going with a set of gap less piston rings which are excellent for sealing up the combustion chamber and providing increased cylinder pressure !
Thanks for the info John..AG
Maybe 5/64 rings, not 5/32? Once you've gone that far with new pistons, wouldn't it make sense to have the block honed with a torque plate, perhaps .005" over and have pistons made to fit so the ring seal would be perfect? Racetec does a great job of making whatever I ask for, it saves the cost of boring the block. I have a 572 tall deck in that I am doing that with right now.
For sure, 5/64 rings, thanks for catching that. AG
Barry, On the ring seal, a MS Sunnen Hone is better for sure, but I have had pretty good leak down results this way. I am trying to do what is best for the customer.AG
@@goldsgarage8236 Yeah, not trying to be too picky, but once you replace crank and rods, might as well put a good piston in it with 1/16 rings and have an all new shortblock. Keep up the good videos!
Those 292 heads made power back in the day.they were good.
As good as it gets back then, thanks David. AG
Have a close look at the ring grooves, if they are worn the new rings won't seal and you'll end up with excessive blowby and potentially oil consumption. Pressing the pistons off is a bit of a gamble because they can distort or even crack during the process. The other weak point is the clip groove, it can be distorted during the removal process. Another consideration is Federal Mogul changed from double tru-arcs to a single round wire lock a number of years back, and the grooves in the pistons are different.
I realize budget is important, but you can buy a budget Eagle balanced rotating kit that's quite inexpensive, it might make more sense in this case because you don't have the labor to remove pistons off rods, have them pin fit, clean up the ring grooves, etc. The new rods are about 50 grams lighter than factory rods, and a new replacement crank is balanced to a mystery bobweight, so you could end up with the dreaded vibration in the mid 2000 RPM range.
Yarrda, you are my mentor, thanks for the info. You have me thinking, or rethinking my plan. These are forged pistons, the bore is on the high side, so i would have to go with forged again if i do replace them. Here is a question, how do you think a 1972 block is standard bore and still in spec, even after at least one rebuild. Thanks as always for good advice.AG
Wow, I didn't expect that much bearing damage! Oil starvation? I remember the rave back then about sbc angled plugs but does it make that much difference? Those pistons look exactly like the TRW's from my '84 vette and it's disappointing that they are press fit. People can get an enitre scat balanced rotating assembly for reasonable prices nowdays thankfully. I would never buy an eagle crank again as I had one break at #7 and found a large void in the casting. Thanks for the follow up!
Good catch on the pistons Greg. , They are TRW 7064P. Standard. AG
Use some brake clean and check for leaking valves on the 40% leak down cylinder. I've never seen 40% leak down from just the rings being lined up.
Thanks DIY, brake clean with air pressure in the cylinder will tell the tale. 5 of 8 cylinders had excellent leak down numbers. I will do a leakdown test again before permanently installing the heads. AG
Thank you for another well done video and keep them coming!!!
Thanks you Grand Prix.AG
Wont you need new pistons also if you go with floating pins?
Ive come to realize there are no budget builds 😅
Thanks Magnus, these pistons have a groove for spirolox so that is what I plan to do. AG
@ alright. I guess I thought spiro pistons couldnt be used with a pressed pin. Not sure I I didnt think it would work.
@@magnusdanielsson2749 You just need to not install the locks.
Interesting debate. For a little more money you can buy new parts OR you can get a machine shop to custom fit your parts. The bearing wear is a real concern. Wouldn't be surprise if there is a crack in the crankshaft in this case and that leans the decision BUT. I want to know why my engine is leaking down 40% eating bearings and knocking. There is a price to this that could very well be worth the investment. .... And then again if I know these engines eat these cranks then I move on. To much missing information to make an informed decision for me here.
Thanks Robert, lots to think about for sure. Your comments compel me to take a closer look. AG
I would place a bet that those heads have date codes that are 1975 at the oldest, as I recall the 292's were first available in '75-'76.
Thanks Alleyoop, I will check the date codes. Memory is getting a little hazy going back to 1975. AG
Stroker kit for a 383 is probably the same cost or very minimum more. I would start with getting the crank magnaflux checked and go from there.
That is an option for sure Dale. Thanks for commenting.AG
My memory is that the 292 'turbo' angle plug heads did not come on any vehicle from the factory. They were only available over the counter from GM around 1975 on
I think you are correct Bob. After a previous comment, I looked it up and the date code is 78. AG
you are correct, the 292 angle pug heads were over the counter only. the 1970 Z/28 and Corvette LT1 heads were 186 casting. the 292 heads were out just prior to the early "Bowtie" heads. the 292 was the first over the counter heads for the SBC for Chevy performance. there were other performance heads the were pushed out the back door to race teams. Like the 461X and 339x heads. the X at the end of the casting indicated that they had bigger intake runners. there was also a strait plug version of the 292 head. casting 492. they were the best flowing heads until the bowties came out, but the Vortec head is still better than any of the camel humps like the 186, 461, 462 or the 292 and 492. the newer Bowtie stuff and pretty much any aftermarket aluminum head is still better. I have quit using cast iron heads for anything but marine application. but for a cheap budge build for a marine small block, I go Vortec every time. summit racing makes a clone of the Vortec but a better casting to prevent the cracks Vortec's are known for. it's my new favorite for any marine small block. and it will take a .490 lift cam out of the box. but can be machined to take a higher lift cam.
@GoldsGarage8236 from what you have described about the bearings and knowing that the engine was around 10:1 compression, and if it was run on pump gas, makes it sound like detonation to me. when detonation happens in an engine the piston is still pushing up in the cylinder and the detonation will cause the piston to transfer the force of the detonation down the connecting rod and into the upper rod bearing, it will also cause the bearing to get "pounded out", losing bearing crush, and loose in the connecting rod bore, exactly like you showed in the example. and it will make the journals on the crank egg shaped. you will also see wear on the bottom of the main bearings as you showed, since the crank is trying to be force out the bottom of the block by the force of the detonation. I would also suspect to see wear on the pin bores on the pistons and maybe the ring lands. Detonation will also cause a lot of heat in the engine, this can damage the ring lands on the pistons and if the engine overheated the rings will lose tension, but I don't think it would cause 40% on one cylinder, so i would suspect the exhaust valve on that cylinder. the exhaust valves run hot on the center two cylinders on angle plug heads to being with, which is why the NASCAR engine builders added coolant hose between them on NASCAR cup engines back in the day. i am betting the exhaust valve on the low cylinders need some work. also, detonation will also cause a blown head gasket. which could also cause the low pressure on the leak down test. it would not be blowing out the intake or exhaust ports. and would sound like it was coming out from inside the engine itself. but would be actually coming out the water passages. I would also look at the head gaskets around those low cylinders.
Thanks Shadvan, a very well thought out analysis, coming from a voice of experience. There is a lot here to consider and comment on, and a few things have changed since this video. i will reply to it in the next video update. thanks for contributing to my channel.AG
I asked total seal lake speed Jr he said leading reason for ring gaps to line up is detonation. I had a Windsor we detonated because poor timing mark on scat balancer and it had both early and new marks on one balancer. always pays to cut a grove on the balancer to tdc is what I learnt from that and set the timing pointer. but basically 4 out of 8 pistons rings lined up engine probably had 2hrs on it and trying to find ignition issue for all of it. race boat motor can't quickly change stuff like a car
Good info Jack, I always verify TDC. AG
383 stroker build is what I would do with 6 inch rods. More power and torque with no downside.
Thanks Jason.AG
At this point, I always give them the option to make it into a 383. Most do.
Good point, thanks Comet. AG
Allan, hows the oiling system look? That's a lot of copper showing on those bearings and all of them, extreme something or other. I'm assuming this engine didn't have a NO2 bottle in the mix.
Good question Vom. It actually has a high volume oil pump and everything else like the cam and lifters are good. The bearings look pretty hammered for sure, but no evidence of overheating. Also no evidence of detonation on the pistons.AG
We had some brownfield heads back then , but they were not much better than ported stock heads.
Thanks Doomman, I haven't heard that name for a while. AG
@ Warren gave us our first good heads. AFR has come a long way since those days.
Rings will self align from time to time since they are not pinned. Been proven to make very little difference in compression or power.
Thanks Jack, you are probably correct, just i couldn't see anything else causing the leakdown. i will check the intake valve. AG
Im finding hard to believe the ring gaps being in line is 40% leak down.
Thanks Justin, I agree. I will check and lap the intake valve on those cylinders. I could not detect any leaks by the exhaust valves. AG
Cylinders get washed out with fuel? Thin out oil and damage bearings?
Thanks Eric, all the damage was on the rod side, looks like it was pounded pretty good. No evidence of heat damage. AG
@goldsgarage8236 Thanks for the education
The bearing falling out is definitely a sign of detonation or pinging
For sure, lucky Paul caught it before it spun.AG
AG I just posted a video of the 383 I built, check it out it sounds awesome! Thank you for your help as always!!
For sure, I will. Thanks and congratulations. AG
Full exhaust car? Overlap and exhaust scavenging are powerful forces. It looks mor like detonation.
That makes sense, but as i said, no evidence on the pistons Scott.AG
Hmm... I'm not convinced compressed air really cares whether or not the ring gaps are aligned. Why would it?
It wouldn't. The gap placement has nothing to do with a leak down result.
This engine has me worried. Seems it was really abused. I would start with a new crank and rods. This is not going to be a cheap rebuild.
Thanks for your comments Steve. I agree. AG
Was he spraying it?
Thanks Scott, it looks like that, but not as far as I know. AG.
Wouldn't that engine have had low oil pressure?
Good question. I did ask the customer about that. He had 15 PSI at idle. The engine had a high volume oil pump or it would have been even lower.AG
Camel hump heads came on belairs to any top model gm got them but vortec heads kill those even with 202 fuelie set up stock vortec is better
Thanks Utah, i agree about the Vortec heads. AG
Labor is just getting too high !…..
Thanks Thomas, it is making it tough for a small scale builder to be competitive with crate engines for sure. AG
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why bother it's only a chev
Ahhh but it's a historical Chev.
What an ASSH*** COMMENT !!! id hope somebody would do your PRIUS that way so You may have a Taste of it LOW LIFE .