TR4/4A Need Advice as to what to do regarding Engine Compression Problems

[rnpennington]

I felt the car wasn’t running right so I skipped an Autocross today to check on it.

First thing I did was a compression test. Results were cylinders 1 – 4: 90, 150, 170, 0.
Added oil to cylinder 1 and 4 results 120, 0.


Could it be just valves or am I realistically looking at an engine rebuild? If valves, should I just have a machine shop do it?


I have done an engine before (VW) many years ago, but want to make sure all is correct the first time.


If I go the engine route, what do you guys think would be a reasonable time/budget. I saw Rimmer has an entire engine rebuild kit for about a grand.


If I do have to rebuild and pull the engine, should I consider replacing the transmission as well?

 

[poolboy]

The last time I had a "0" compression reading it was because of this.

 

[rnpennington]

Well, That's encouraging......................NOT.
After I pull the head I will let you know if I can match your picture

 

[GerryL]

You should check valve lash before doing anything else. A valve lash setting that is too tight will prevent valves from completely closing on their sears and will result in loss of compression.

 

[rnpennington]

Thanks - I just got back from a 400 mile trip. It ran fine on the way down and while we were driving around town. On the way back, after a couple of hours, it seemed a little fiddley, but as my generator fan started rattling and making a tremendous noise, I just attributed it to may imagination. A few trips around town, there was a definite lack of acceleration, hence the check started and the fun begins

 

[Geo Hahn]

Thanks - I just got back from a 400 mile trip...

Before I rebuilt my TR4 head with hardened seats I had major recession after a 400 mile run at high speed -- lost the gap completely. In my case the valves had receded enough that no adjustment was enough -- so the decision to rebuild was an easy one.

 

[rnpennington]

If you don't mind sharing, what did you pay and what was done so I have point of reference

 

[Andrew Mace]

Thanks - I just got back from a 400 mile trip. It ran fine on the way down and while we were driving around town. On the way back, after a couple of hours, it seemed a little fiddley, but as my generator fan started rattling and making a tremendous noise, I just attributed it to may imagination. A few trips around town, there was a definite lack of acceleration, hence the check started and the fun begins

That description kinda would make me want to check the valve clearances first. Also, a fairly easy way to rule out piston/ring problems would be to repeat the test after dribbling a bit of oil down the spark plug hole. If compression readings rise significantly, then you might have, say, cracked rings. If there's no change, you'll probably be looking at the valves and related bits...or (just possibly, but not very likely in this case) head gasket problems.

 

[Geo Hahn]

If you don't mind sharing, what did you pay and what was done so I have point of reference

If you're asking about the head work I had done -- the bill from the machine shop was $340.92. They provided the seats (4) and guides (8), I provided new valves & springs.

They cleaned the head in that big (whatever they use), resurfaced the head and installed everything.

 

[poolboy]

I think Pennington said he still got zero psi compression after adding oil, Andrew.
BTW, my engine was pretty noisy, too with that connecting rod banging around in the cylinder, but before that it made a tremendous rattling noise while the piston was being chewed up and spit down into the sump.

 

[rnpennington]

Well,
Since either way I will need the head checked and valves done, I guess I'll start there and see what happens -assuming I don't see a big hole where the piston should be. I figure worst case basis I get to remove the head a second time and a few gaskets.

 

[poolboy]

Yeah, and since you also live in down here in a hurricane prone zone, you're probably familiar with this, "prepare for the worst and hope for the best".

 

[rnpennington]

Only too well

 

[tdskip]

Fingers crossed for you. Keep us posted.

 

[rnpennington]

Fixing the cylinder head - one of those "While I'm in the neighborhood"" - any other maintenance work you guys recommend? Timing chain, etc?

Also, There is a local shop highly recommended here in Houston -Westside Performance & Machine - but I saw this place on the web and I was wondering if anyone has any experience with them https://www.wishboneclassics.com/content/rebuilt-tr4-tr4a-high-port-cylinder-head as a fixed cost of 675.00 sounds good, after looking into the parts prices.

Also, at this time I should repaves all the valves and get hardened seats correct for unleaded use. Any other suggestions?

 

[TexasKnucklehead]

Bob,

I really think you need to try a valve lash adjustment first, before jumping into the head. You may have something as simple as a bent push rod, or a broken lifter, or a lobe missing from your cam... not that those are good things to have, but knowing what your failure is, is a better place to start. You might be able to tell the problem just by pulling off the cover and watching the dead cylinder.

If you go the head route, Mike Hado in our club is the best person to talk to. He and I took my head to the place you mentioned. Yesterday, we were autocrossing without you and the competition was great.

Good luck, call me if you need a hand,
Jerry

 

[rnpennington]

Jerry,
Thanks, I've already talked to Mike about this

 

[Andrew Mace]

I think Pennington said he still got zero psi compression after adding oil, Andrew.

Right; I missed that. My bad.

 

[rnpennington]

Well, Here are the results.........................
A fellow club member here in Houston Texas Knucklehead (very misnamed) came by to help me sort it out. Problem solved. The valves on cylinder #4 had tightened up and never fully closed. He helped me adjust the valves and everything is WONDERFUL. Compression between 150 and 165 across the board, runs smoothly.

Thanks for all your advise and a great big thanks to Texas Knucklehead for taking the time to come by and help.

Soapbox mode on:
This is why you should join and be active in a club if one is nearby. The ability to call upon one another for help and to help one another out cannot be measured. Besides the usual camaraderie and fun get-togethers, the bottom line is we are all in this together and as Alexander Dumas so succinctly wrote may years ago - All for One and One for All.
The forums are great for helping one another out and I promise I will be a more active participant in the future, but one on one human touch is still the best. And that's what clubs are for. Forget Robert's Rules of Order and all that - its so " we few, we happy few, we band of brothers;" can be there for one another.

Soapbox Mode Off

 

[poolboy]

You should go and buy a Lotto ticket cause you are one lucky...!