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Tips and pointers for 403 "build" with #6 heads needed
Hi guys!
I'm new to this forum, even though I have owned my 1978 Trans Am for 9 years. I live in Sweden, Scandinavia. Was mostly hanging out on 78ta.com forum before, lately I have been finding myself coming back to the forums after a break.
I have as said, a Pontiac Trans Am with the 403 Oldsmobile. I installed the Thornton JR 350 manifolds, true dual exhaust and a Comp Cams XE262 cam kit a couple of years ago, and it's been running good since that.
However, wanted more, and did find a set of 1970 #6 Olds 350 heads for cheap. I delivered them to a machine shop this winter, and they have installed new valve guide sleeves (K-line), put in 1.995" intake valves, opened up the bowls and grinded away the EGR hump in the exhaust ports. They will also mill the heads to compensate for the Fel-Pro head gasket thickness that I will use. How can I determine whether or not the heads have been milled before? How much should they mill to compensate fully for the Fel-Pro gasket? I don't want to mill the intake (a new 2711 Edelbrock Performer) to fit it.
I took off the old 4A heads last weekend, and I unfortunately found out that 7 of the 16 Comp cams High Energy lifters had broken clips. Only found 4,5 clips, so that means that 2,5 clips is laying somewhere in the engine. Hopefully in the screen mesh of the oil pump pickup. So I am going to lift out the rest of the engine too, to look for the clips. This is a budget build, so if I do find the clips, what should I ABSOLUTELY DO with the bottom end when it is out of the car? It has good and even compression. Drained the oil and cut open the oil filter, and there's no metal shavings, and has not been any before either, as I have a habit of checking the oil each oil change with a magnet.
Anyone have a recommendation for replacement lifters? I don't know if I trust the Comp Cams lifters anymore to buy a new set. Same here, budget = good. I can get Crane Cams, Comp Cams, Summit brand or Sealed Power in Sweden. Sealed Power is probably a stock replacement, so too weak, right?
I have been offered a used set (80 hours in a boat engine) of the Comp Cams Magnum stamped steel roller tip rockers with studs, poly locks and guide plates for a good price, no pushrods though, since the set the guy has is the 1442-KIT for a 455, and as far as I can tell, the difference between that kit and the 1441-KIT is the pushrods length, right?
Will measure pushrods length, but what brand/series pushrods would be a good, economical choice?
The cam is as I said a XE262. I also have 3.23 gears and a higher rpm stall converter. Is that cam acceptable in this build? I see recommendations on the Engle TQ40, but that seems to be a good part more aggressive cam compared to the one I have? I'm not looking to get a monster engine, I would be happy with close to 300 hp. Gas is expensive in Sweden... Thanks in advance for any help!
I believe Summit lifters are US made which is a good thing. Doesn't mean much for the brand anymore, more where it is made and quality control. Your current cam will be fine with around 9 to 1 compression. You need to CC the heads to if they have been cut and how much. If they measure 68 to 70cc, they are probably untouched. You can cut the heads .020", since the factory shim gaskets with the 350 were .017" to .018" thick. Use the Turkey tray gasket, composite gaskets will be too thick, get the Felpro 96009 for the early heads https://www.google.com/url?sa=t&sour...wBgcLNyfoVzQbC, the exhaust crossover in the head is bigger in later heads like your 4A heads. So later gasket will cause a leak. Those roller tip rocker arms will work. You either conversion 5/16" bottom and 3/8" top studs, Comp offers them or drill and tap the heads for 3/8" studs. Get a checker pushrod to figure out push rod length. I have 8.5" pushrods on mine but my heads were milled to 55cc chambers. Use the matching springs from Comp cam and 1.625" exhaust valves are a good match, being both were used with the W31 motors. Also make sure the machine shop uses a bowl cutter under the valves when installing bigger valves. I picked up a set of #6 heads someone did like you are planning for $400. They put 2.05" intake valves, stock 1.56" exhaust valves, bowls opened, new guides, upgraded springs and positive seals. Good luck, hope this helps.
The one thing I didn't see you mention in the head bolt holes. The 403 uses ˝" bolts where the 6 heads are drilled for 7/16" bolts. Make sure the machine shop knows they are going on an engine with ˝" bolts.
The one thing I didn't see you mention in the head bolt holes. The 403 uses ˝" bolts where the 6 heads are drilled for 7/16" bolts. Make sure the machine shop knows they are going on an engine with ˝" bolts.
Yes, that has been done, we had a little trouble figuring out what size to drill the holes though. We took them to 17/32. Didn't bother to mention it in my thread start, sorry...
Well. If youve been happy with your combination, maybe rering it and check journals, change bearings if needed. Then just put it back together assuming you find all the broken circlips.
Measure how far down in the hole the pistons are, not quess, and from there calculate, taking head-gasket on equation, what chamber volume you need to get your desired compression. Then get a new set of lifters and those magnum roller-tip rockers, and call it done. That would be cheapest.
About lifters im not taking any part whos best. Just some tought, was your valvetrain set up correctly, just came to my mind from broken circlips. And forget the "where its made" nonsense, Chinese does as good stuff as anyone else in the World, if paid for it. Problem is, bean-counters ordering cheap crap from them, and when it brokes, it just easy to blame overseas manufacturer other side of the World. I bought a set of Hedman Hedders which proudly state made in USA big at the package, and the collectors werent even close to fitting to headers, needed some work to fit. And the flange to head is questionable at best. So there goes "Premium product QC.."
Btw, Greetings from neighbour.
Last edited by Inline; March 28th, 2019 at 10:44 PM.
Thanks for the reply!
So Summit HT-951 could be a good choice? They have the same Product # as Sealed Power lifters?
Thanks for the info on the intake gasket, I didn't know that about the larger exhaust crossover port!
Lots of good stuff in your post!
I'm going to leave the stock exhaust valves in place. I figure it will be a big difference anyway, getting rid of the A.I.R rod sticking in to the exhaust port...
Originally Posted by olds 307 and 403
I believe Summit lifters are US made which is a good thing. Doesn't mean much for the brand anymore, more where it is made and quality control. Your current cam will be fine with around 9 to 1 compression. You need to CC the heads to if they have been cut and how much. If they measure 68 to 70cc, they are probably untouched. You can cut the heads .020", since the factory shim gaskets with the 350 were .017" to .018" thick. Use the Turkey tray gasket, composite gaskets will be too thick, get the Felpro 96009 for the early heads https://www.google.com/url?sa=t&sour...wBgcLNyfoVzQbC, the exhaust crossover in the head is bigger in later heads like your 4A heads. So later gasket will cause a leak. Those roller tip rocker arms will work. You either conversion 5/16" bottom and 3/8" top studs, Comp offers them or drill and tap the heads for 3/8" studs. Get a checker pushrod to figure out push rod length. I have 8.5" pushrods on mine but my heads were milled to 55cc chambers. Use the matching springs from Comp cam and 1.625" exhaust valves are a good match, being both were used with the W31 motors. Also make sure the machine shop uses a bowl cutter under the valves when installing bigger valves. I picked up a set of #6 heads someone did like you are planning for $400. They put 2.05" intake valves, stock 1.56" exhaust valves, bowls opened, new guides, upgraded springs and positive seals. Good luck, hope this helps.
Last edited by Mikekop; March 29th, 2019 at 02:25 AM.
Reason: Wrong word
Hi Inline!
Neighbor? Are you in Scandinavia? Norway, Finland or Denmark?
What do you mean by "rering it" ?
When I installed the cam kit, I reused the stock aluminum pedestals, and we (I had a guy helping me) did do the" spin the pushrods" procedure while tightening the bolts, until the pushrods couldn't be spun by hand, and it then remained 1/2 turn to correct torque. The lifters was pre-soaked in oil. I chatted online with Comp Cams a couple of days ago, and the tech guy approved of this method. However, I quickly developed a rocker clatter, which came from the aluminum pedestal pivots being worn down, so I replaced all the pedestals with the steel pivot ***** and bridge that my parts store listed as stock replacement. Thinking they were stock replacement, I never rechecked the lash. However, the valve train has been silent since then... I did find a thread here on Classic Olds where the exact same thing had happened to the exact same lifters (I replied to that thread, so it is just a couple of posts down). And I just saw on Summit Racing that some customers has reported that the same lifters they had bought had stuck plungers? I don't know, but those Comp Cams lifters seems dodgy?
I hear you on where the parts are made, I just want a lifter that won't fail on me. I see that the Summit brand does have real C-clips (if the image is correct) instead of the ones in the Comp Cams lifters, that looks like it's made out of a paper clip.
Originally Posted by Inline
Well. If youve been happy with your combination, maybe rering it and check journals, change bearings if needed. Then just put it back together assuming you find all the broken circlips.
Measure how far down in the hole the pistons are, not quess, and from there calculate, taking head-gasket on equation, what chamber volume you need to get your desired compression. Then get a new set of lifters and those magnum roller-tip rockers, and call it done. That would be cheapest.
About lifters im not taking any part whos best. Just some tought, was your valvetrain set up correctly, just came to my mind from broken circlips. And forget the "where its made" nonsense, Chinese does as good stuff as anyone else in the World, if paid for it. Problem is, bean-counters ordering cheap crap from them, and when it brokes, it just easy to blame overseas manufacturer other side of the World. I bought a set of Hedman Hedders which proudly state made in USA big at the package, and the collectors werent even close to fitting to headers, needed some work to fit. And the flange to head is questionable at best. So there goes "Premium product QC.."
From Finland. Been visiting many times at Sweden ( driving through Stockholm to Göteborg on way to south Europe ).
Nah, i somehow missed that it has good and even compression, and i suppose its not using oil? So forgot the re-ring part, i quess your good at that department.
Just to add for lifters, just checked that ( whoever makes them) Howards lifters have that "paperclip" you described.
Those valve lifter "paper clips" are crap (dodgy). They are a round wire fitting in a square groove and fits in the groove only partially around. An "old school" tip/trick was to use a proper internal snap ring. The internal snap ring has a square shape and engages the groove deeper and almost 360 degrees around. Perhaps "Inline(from Finland)" can translate for you.
Ok, nice! Ever visited Classic Car Week in Sweden, Rättvik? I live very close to Rättvik.
I get now what you mean by rering, or re-ring like it should be read, like in honing the cylinder bore and putting in new piston rings. Yes, good compression, and it doesn't use one drop of oil, I drove it to Umeĺ and back last summer, which is a 1200 km ride in highway speed/RPM (3000 rpms in my case) and it didn't miss a beat, and no oil usage.
As my brother use to say, don't repair anything that's not broken, so I'm kind of scared to unbolt the crank to check the bearings... Does the bolts holding the journal "half moon" need to be replaced if I loosen it?
I am considering replacing the oil pump though.
Originally Posted by Inline
From Finland. Been visiting many times at Sweden ( driving through Stockholm to Göteborg on way to south Europe ).
Nah, i somehow missed that it has good and even compression, and i suppose its not using oil? So forgot the re-ring part, i quess your good at that department.
Just to add for lifters, just checked that ( whoever makes them) Howards lifters have that "paperclip" you described.
Do you feel OK with just replacing a single lifter? Is there actually any difference in performance between lifters, or is that only fancy words from the manufacturer?
Originally Posted by olds 307 and 403
I believe there are only a couple of lifter manufacturers. I also have a stuck lifter and plan on replacing it with a Summit lifter.
Personally; i would replace separate lifter only if using the exact same lifter as the rest. Theres a possibility that they have different bleed rates / plunger travels. Just "possibility" since i havent tested that. Any possibility that those lifter clips may have broken when you were having issues with worn aluminium pedestals? Did you check them back then?
Id just pop few caps and look for lower bearing surfaces and crank bearing surface, and if they look good, just bolt it back since this is budget build. If you want you might test few with plastigage. And while at it, you might aswell test the end-to-end movement of crank. Nr.3 cap has thrust bearing. If you mean crankshaft bolts holding bearing caps, just re-use them. That would be simple enough quick look-ups i might do.
Never been at Rättvik, but Umeĺ, there i have spend a week once. Came with a ship from Vaasa.
OLDster Ralph - cant tell it better than that No idea what interal snap-ring is for sweden.
Don't worry, I'll be replacing all 16 lifters! For now, I'm still trying to figure out what lifters to go with. Will try to get ones with the internal snap ring (which I understood perfectly) and avoid the paper clip type.
I don't know when the clips broke, but I feel like it's unlikely that they have been broken that long without causing serious damage? I mean damage by the broken clips floating around in the engine. But I have no idea really.
I'll definitely take off a few caps and check the surface of the bearings and crank, that shouldn't be too hard.
Thanks for all the advice!
Originally Posted by Inline
Personally; i would replace separate lifter only if using the exact same lifter as the rest. Theres a possibility that they have different bleed rates / plunger travels. Just "possibility" since i havent tested that. Any possibility that those lifter clips may have broken when you were having issues with worn aluminium pedestals? Did you check them back then?
Id just pop few caps and look for lower bearing surfaces and crank bearing surface, and if they look good, just bolt it back since this is budget build. If you want you might test few with plastigage. And while at it, you might aswell test the end-to-end movement of crank. Nr.3 cap has thrust bearing. If you mean crankshaft bolts holding bearing caps, just re-use them. That would be simple enough quick look-ups i might do.
Never been at Rättvik, but Umeĺ, there i have spend a week once. Came with a ship from Vaasa.
OLDster Ralph - cant tell it better than that No idea what interal snap-ring is for sweden.
Update:
I have pulled the bottom end out of the car, and eventually found almost all of the lifter clips. All but 3/4er of one clip was stuck in the mesh screen of the oil pick up. The 3/4 piece has passed through the oil pump and messed up the sprockets in it. It's a miracle that it hasn't seized and destroyed the engine... I have pulled a couple of the main caps, and I think the bearings look good, anyone else?
I have bought a new oil pump and pick up. Ordered Lunati lifters, they have the proper internal lock ring, and not the paper clip ones.
Good grief that's a mess. Get some plastigauge and check your clearances on all of the bearings. It's not hard, just a little time consuming. You have to do a good visual on all of the bearings and journals anyway, so this is cheap insurance that nothing is out of spec.
They are color coded on thickness so you need to get the specs for both the crank and rod clearances before you go and buy what you need. It's cheap enough at the parts store and you shouldn't have to buy a whole box. We sold it buy the stick.
Red, blue, green and yellow (not shown).
Update:
It was too early to get confident. Ran out of luck.
#1 main bearing was heavily scored. #4 had a subtle score, just enough to be able to feel it with my nail. I have yet to check #5, ran out of time today. I did measure the #2 and 3 bearing, and it was well within specs, the technical manual says that up to .0035" is ok.
Will continue on Sunday to check #5 bearing, and the rod bearings too.
Hows the journal on the crank? It might be good still, since bearing material is alot softer and eats the irregularities, ie. foreign parts on oil. You can swap crank bearings without taking the crank off.
The journal looks good, and yes, I read the procedure to change bearings with crank still in place. My parts place didn't have the standard size bearings in stock, otherwise I could have put new ones in this weekend...
Well, then your not having problem at all. Sounds good. Btw. Whats all that other crap on the picture of oil pump gears? All of that cant be from the gears by looks. Just came to my mind, if they aint pieces of oil-pan gasket, are there pieces of timing-chain sprocets..? Id say you got on to that engine just in time to get saved from alot bigger and costly repair.
It is pieces of the nylon coating on the original timing chain sprockets, so you were spot on. They were all stuck in the mesh screen on the oil pickup. I'm beginning to think this engine is immortal?
Update:
Removed main bearing cap #5, and it looked good. Moved on to connecting rods, and the second bearing I took off had scoring (see picture), so I stopped there, will be replacing all bearings, and no need to open the remaining rod caps until I have the new bearings.
Do I need to put new nuts on the connecting rod caps?
I measured the rod journals on the crank, but I can't think today it seems, can't figure out what the measurement is for them, they are supposed to be 2.1248" - 2.1238" according to shop manual. Can someone please interpret the caliper measurements on the picture for me?
That's why I'm measuring them. I plastigaged it, and the clearance was slightly more than .0015", which is well within spec. I just measured to check if I can buy standard size bearings. So, can I?
Originally Posted by cutlassefi
Don't measure a journal with calipers other than to verify whether theyre std, .010 or whatever. Otherwise very inaccurate.
Id say to look backside of bearings to see if they have any kind of stamping, that should tell you the size.
Those calipers are really vague, numbers you gave turns to 53.94-53.97mm, which your calipers seems to roughly show, but but… They might be just that much off.
I always turn all the numbers to metric, since we dont have any quality measurement devices with inches shown until you pay top top money for them, or order from internet. Metric micrometers you can get from closest "better" toolshop.
Googling just shows its GM rod bearing for Oldsmobile. Dont know what size. Somebody might know GM markings. If thats the only marking, they might be std. One could thing they would add stamp like 010 etc for undersize.
I suggest to loan micrometer or buy one, if someone cant tell.
Id say thats std size, .010 undersize would be roughly 53.7mm. Question remains how accurate your calipers are? Especially cheap ones are crapshoot when verified with micrometer.
You can get standard size bearings, may as well throw on fresh rings as well. As said, make sure they are standard size. I picked up a 403 from a wrecker, supposedly old man owned. It may have been, but it had Detroit head gaskets and .010" rod bearings. Either way you will have some reliable, added power when done.
Update: I measured the rod journals on the crank, but I can't think today it seems, can't figure out what the measurement is for them, they are supposed to be 2.1248" - 2.1238" according to shop manual. Can someone please interpret the caliper measurements on the picture for me?
Without sounding harsh, you are using one of the most primitive measuring instruments. Your pic has a skewed view of the vernier scale. It seems to be pressure thumb roll and don't see a lock. How much wear is present on the jaws ? How much are they sprung ? A micrometer is the only accurate tool to use. This might work for an approximation. The TOP scale is fractional measurement. Each space is 1/16" (inch) and NOT capable of DECIMAL numbers without conversion. It shows 2 1/8 inches.......comparable to 2.125 decimal inches. You need a digital calipher that can measure in either metric or inches....for ROUGH MEASUREMENTS.
You need a digital calipher that can measure in either metric or inches....for ROUGH MEASUREMENTS.
I disagree about needing digital. Since we live in Europe, that caliper has been done to metric, not inch-system. It goes down to .002" inch accuracy on metric side, which is plenty enough for rough measurements. Just needs to convert inches to mm, and these work as good as digitals.
Ok, thanks Inline and Olds 307 and 403! I checked the inaccuracies online for a cheap digital caliper, and it is pretty much the same inaccurate as the tolerances on the journal, about .001". But it should be accurate enough to measure if undersized bearings are needed or not. I'll see if I can borrow a high quality digital caliper instead, shouldn't be a problem.
The head gasket on this one was a Fel-Pro, and that had me confused for a while, until I read online that it was what the factory used on the 403, and the part # was not the same as my newish head gasket.
How about those connecting rod cap nuts, do I need to replace them?
Last edited by Mikekop; April 7th, 2019 at 10:04 AM.
That's why I'm measuring them. I plastigaged it, and the clearance was slightly more than .0015", which is well within spec. I just measured to check if I can buy standard size bearings. So, can I?
From what I am seeing on those primitive vernier caliphers, it appears you have 2 1/8 inch journals........2.125 decimal inches. 2.1248 inches would appear that they are standard diameter journals.
Thanks Ralph, that was a very good explanation of the reading method of the scale. It's not a problem for me to borrow a more accurate digital caliper, or even a micrometer, so I'll do that before buying bearings.
Thanks everyone for "bearing" (haha, pun intended :-D) with me, this is my first time doing this, I'm just a carpenter... I may ask stupid questions, but I'm a fast learner, and I do have a little more than just saw dust for brains
Originally Posted by OLDSter Ralph
From what I am seeing on those primitive vernier caliphers, it appears you have 2 1/8 inch journals........2.125 decimal inches. 2.1248 inches would appear that they are standard diameter journals.
I disagree about needing digital. Since we live in Europe, that caliper has been done to metric, not inch-system. It goes down to .002" inch accuracy on metric side, which is plenty enough for rough measurements. Just needs to convert inches to mm, and these work as good as digitals.
Inline, your point is well taken. Mike is working on American cars and they are "inch system" and converting can lead to mathematical errors in conversion. By pressing the "mm button" you convert to metric, and back again numerous times. For people who don't use or convert frequently, it does help. Inline, like you I convert things...... but I convert metric to inch for my comprehension. I know that ,1 = .004" approximately. 1mm = .03937 inches. Most caliphers are accurate to .002 inches, would that be ,05 ? I suspect you have been around machinery enough to be confident and competent. Mike is learning and seems to be doing a great job of it. ........Just my two cents worth (Dayum, now I am wondering what $.02 is in Finish or Swedish currency).
Inline, your point is well taken. Mike is working on American cars and they are "inch system" and converting can lead to mathematical errors in conversion. By pressing the "mm button" you convert to metric, and back again numerous times. For people who don't use or convert frequently, it does help. Inline, like you I convert things...... but I convert metric to inch for my comprehension. I know that ,1 = .004" approximately. 1mm = .03937 inches. Most caliphers are accurate to .002 inches, would that be ,05 ? I suspect you have been around machinery enough to be confident and competent. Mike is learning and seems to be doing a great job of it. ........Just my two cents worth (Dayum, now I am wondering what $.02 is in Finish or Swedish currency).
Thats very true, that it removes alot of confusion when the caliper converts the number with a press of button, no chance for convert error, atleast error by human.
.002" is roughly .05mm, actually its not .002", its something like .0019xxx" but .002" will do
Hmm.. Your two cents would be either 0.19 öres ( currency at Sweden is Krone, SEK) or 0.02 cents ( at Finland, we use Euro, €)
March 28th, 2019, 01:01 PM
).
No idea what interal snap-ring is for sweden.
. Check all the bearings to be safe and a new oil pump is in your future.
